diff --git a/jerry-core/parser/js/opcodes-dumper.cpp b/jerry-core/parser/js/opcodes-dumper.cpp
index 3414747b0..8b28f8bf0 100644
--- a/jerry-core/parser/js/opcodes-dumper.cpp
+++ b/jerry-core/parser/js/opcodes-dumper.cpp
@@ -311,9 +311,8 @@ dumper_try_replace_var_with_reg (scopes_tree tree, /**< a function scope, create
       {
         om.lit_id[arg_index] = NOT_A_LITERAL;
 
-        raw_instr *raw_p = (raw_instr *) (&om.op);
-        JERRY_ASSERT (raw_p->uids[arg_index + 1] == VM_IDX_REWRITE_LITERAL_UID);
-        raw_p->uids[arg_index + 1] = reg;
+        JERRY_ASSERT (om.op.data.raw_args[arg_index] == VM_IDX_REWRITE_LITERAL_UID);
+        om.op.data.raw_args[arg_index] = reg;
       }
     }
 
diff --git a/jerry-core/parser/js/scopes-tree.cpp b/jerry-core/parser/js/scopes-tree.cpp
index a8120f090..2f14d495f 100644
--- a/jerry-core/parser/js/scopes-tree.cpp
+++ b/jerry-core/parser/js/scopes-tree.cpp
@@ -30,19 +30,17 @@ assert_tree (scopes_tree t)
 }
 
 static vm_idx_t
-get_uid (op_meta *op, uint8_t i)
+get_uid (op_meta *op, size_t i)
 {
-  JERRY_ASSERT (i < 4);
-  raw_instr *raw = (raw_instr *) &op->op;
-  return raw->uids[i + 1];
+  JERRY_ASSERT (i < 3);
+  return op->op.data.raw_args[i];
 }
 
 static void
-set_uid (op_meta *op, uint8_t i, vm_idx_t uid)
+set_uid (op_meta *op, size_t i, vm_idx_t uid)
 {
-  JERRY_ASSERT (i < 4);
-  raw_instr *raw = (raw_instr *) &op->op;
-  raw->uids[i + 1] = uid;
+  JERRY_ASSERT (i < 3);
+  op->op.data.raw_args[i] = uid;
 }
 
 vm_instr_counter_t
diff --git a/jerry-core/vm/opcodes.h b/jerry-core/vm/opcodes.h
index 4f7b1e692..6b2d15193 100644
--- a/jerry-core/vm/opcodes.h
+++ b/jerry-core/vm/opcodes.h
@@ -257,6 +257,14 @@ typedef struct vm_instr_t
     } opcode_name;
 
 #include "vm-opcodes.inc.h"
+
+    /**
+     * Opcode-independent arguments accessor
+     *
+     * Note:
+     *      If opcode is statically known, opcode-specific way of accessing arguments should be used.
+     */
+    vm_idx_t raw_args[3];
   } data;
 } vm_instr_t;
 
@@ -300,10 +308,4 @@ typedef ecma_completion_value_t (*opfunc) (vm_instr_t, vm_frame_ctx_t *);
 
 #include "vm-opcodes.inc.h"
 
-
-typedef struct
-{
-  uint8_t uids[4];
-} raw_instr;
-
 #endif /* OPCODES_H */
diff --git a/jerry-core/vm/pretty-printer.cpp b/jerry-core/vm/pretty-printer.cpp
index 907539140..54b67d1d8 100644
--- a/jerry-core/vm/pretty-printer.cpp
+++ b/jerry-core/vm/pretty-printer.cpp
@@ -95,23 +95,22 @@ tmp_id_to_str (vm_idx_t id)
 static const char *
 var_to_str (vm_instr_t instr, lit_cpointer_t lit_ids[], vm_instr_counter_t oc, uint8_t current_arg)
 {
-  raw_instr raw = *(raw_instr*) &instr;
-  if (raw.uids[current_arg] == VM_IDX_REWRITE_LITERAL_UID)
+  JERRY_ASSERT (current_arg >= 1 && current_arg <= 3);
+
+  if (instr.data.raw_args[current_arg - 1] == VM_IDX_REWRITE_LITERAL_UID)
   {
-    if (lit_ids == NULL)
-    {
-      return "hz";
-    }
+    JERRY_ASSERT (lit_ids != NULL);
     JERRY_ASSERT (lit_ids[current_arg - 1].packed_value != MEM_CP_NULL);
+
     return lit_cp_to_str (lit_ids[current_arg - 1]);
   }
-  else if (raw.uids[current_arg] >= 128)
+  else if (instr.data.raw_args[current_arg - 1] >= 128)
   {
-    return tmp_id_to_str (raw.uids[current_arg]);
+    return tmp_id_to_str (instr.data.raw_args[current_arg - 1]);
   }
   else
   {
-    return lit_cp_to_str (serializer_get_literal_cp_by_uid (raw.uids[current_arg], NULL, oc));
+    return lit_cp_to_str (serializer_get_literal_cp_by_uid (instr.data.raw_args[current_arg - 1], NULL, oc));
   }
 }
 
@@ -134,14 +133,12 @@ pp_printf (const char *format, vm_instr_t instr, lit_cpointer_t lit_ids[], vm_in
     {
       case 'd':
       {
-        JERRY_ASSERT (current_arg <= 3);
-        raw_instr raw = *(raw_instr*) &instr;
-        printf ("%d", raw.uids[current_arg]);
+        JERRY_ASSERT (current_arg >= 1 && current_arg <= 3);
+        printf ("%d", instr.data.raw_args[current_arg - 1]);
         break;
       }
       case 's':
       {
-        JERRY_ASSERT (current_arg <= 3);
         printf ("%s", var_to_str (instr, lit_ids, oc, current_arg));
         break;
       }
@@ -159,8 +156,8 @@ pp_printf (const char *format, vm_instr_t instr, lit_cpointer_t lit_ids[], vm_in
 #define PP_OP(op_name, format) \
   case op_name: pp_printf (format, opm.op, opm.lit_id, oc, 1); break;
 #define VAR(i) var_to_str (opm.op, opm.lit_id, oc, i)
-#define OC(i, j) __extension__({ raw_instr* raw = (raw_instr *) &opm.op; \
-                                 vm_calc_instr_counter_from_idx_idx (raw->uids[i], raw->uids[j]); })
+#define OC(i, j) __extension__({ vm_calc_instr_counter_from_idx_idx (opm.op.data.raw_args[i - 1], \
+                                                                     opm.op.data.raw_args[j - 1]); })
 
 static int vargs_num = 0;
 static int seen_vargs = 0;
@@ -174,7 +171,7 @@ dump_asm (vm_instr_counter_t oc, vm_instr_t instr)
 
   for (i = 1; i <= opcode_sizes[opcode_id]; i++)
   {
-    printf ("%4d ", ((raw_instr *) &instr)->uids[i]);
+    printf ("%4d ", instr.data.raw_args[i - 1]);
   }
 
   for (; i < 4; i++)